Electric radiation device



Patented Aug. 28, 1934 UNITED STATES ELECTRIC RADIATION DEVICE Kurt Wiegand, Berlin, Germany, assignor to General Electric Company, a corporation of New York No Drawing.

Application October 7, 1927, Serial No. 224,757. In Germany November 3, 1926 2 Claims.

The present invention relates to electric glow discharge devices, and in particular to devices for producing chemically active radiations, such as ultraviolet radiation.

5 It is the object of my invention to provide an improved source of such radiations, and especially a source of ultraviolet which is operable at a lower temperature than the devices heretofore used for such purposes, for example, quartz mercury arc lamps.

These are devices operate at such a high temperature that a relatively large air space is required between the arc device and the materials being treated. This fact entails an inefficient use of the ultraviolet radiation. It has been proposed heretofore to use in place of mercury arc lamps a glow discharge device of the type commonly known as the Moore tube which is filled with a gas such as nitrogen or carbon dioxide at low pressure. As devices of this type operate at lower temperatures the materials being treated can be brought directly into contact with the tube and the duration of treatment therefore can be materially reduced.

In accordance with the present invention the ultraviolet output of a Moore tube or similar type of glow device is increased, thereby rendering possible production of a given sterilizing effect in a shorter time. A device embodying this invention comprises a glow device having an envelope consisting of material permeable to ultraviolet, such, for example, as silica or uviol glass, and containing a mixture of nitrogen and mercury vapor. In the present form of the invention hydrogen is also present in addition to these gases. In carrying out my invention an envelope of silica or uviol glass containing suitable electrodes and having ordinarily the usual tubular form is evacuated as usual and then is filled with nitrogen at reduced pressure.

introduced into the device and preferably also some hydrogen. The nitrogen gas may have a pressure of 0,05 to 1 millimeter of mercury. The ultraviolet radiation field of nitrogen can be practically utilized up to only 280 a a. The ultraviolet radiation of mercury, however, can be advantageously utilized up to 220 a Furthermore, a better energy distribution is obtained by the addition of mercury vapor to the nitrogen and consequently a more uniform distribution of the spectral lines. The proportion of the hydrogen A drop of mercury is also 7 far as possible as its presence reduces the lighting efiiciency of such lamps. In the present device, which is intended for a different purpose, the presence of hydrogen is an advantage.

The addition of the mercury vapor into glow discharge devices does not produce any substantial increase in operating temperature of the device as the mercury vapor is used only as an auxiliary carrier of the discharge. For the operation of a mercury vapor arc lamp of a given length a current of about 3 amperes is required. For the present glow discharge device containing nitrogen and mercury vapor a current of only about 50 to 80 milliamperes is required. This decrease in operating current entails also a decrease of operating temperature and therefore permits such devices to be brought into direct contact with a liquid to be treated with ultraviolet in such processes as sterilization, polymerization, bleaching or vitamin enrichment.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. An electric discharge ultra-voilet generating device for ultra-violet treatment comprising an envelope permeable to ultra-violet radiation having solid electrodes sealed therein and containing a light radiant mixture comprising nitrogen, mercury vapor and hydrogen.

2. An electric discharge ultra-violet generating device comprising an envelope permeable to ultraviolet radiation having solid electrodes sealed therein and containing light radiant mixture of gases therein rich in ultra-violet radiation, said mixture comprising a discharge supporting gas in major proportion, a vaporizable material and 9 another gasin minor proportion.

KURT WIEGAND.

to the nitrogen may be about 98 parts nitrogen and 2 parts hydrogen. In the Moore illuminating device with an ordinary glass bulb a special ef- 55 fort has been made to eliminate the hydrogen as 

